Switching apparatus including gating circuitry for actuating micro-electromechanical system (MEMS) switches

Abstract

A switching apparatus, as may be configured to actuate stacked MEMS switches, may include a switching circuitry ( 34 ) including a MEMS switch ( 36 ) having a beam ( 16 ) made up of a first movable actuator ( 17 ) and a second movable actuator ( 19 ) electrically connected by a common connector ( 20 ) and arranged to selectively establish an electrical current path through the first and second movable actuators in response to a gate control signal applied to the gates of the switch to actuate the movable actuators. The apparatus may further include a gating circuitry ( 32 ) to generate the gate control signal applied to gates of the switch. The gating circuitry may include a driver channel ( 40 ) electrically coupled to the common connector and may be adapted to electrically float with respect to a varying beam voltage, and may be electrically referenced between the varying beam voltage and a local electrical ground of the gating circuitry.

The invention claimed is: 
     
       1. A switching apparatus comprising:
 a switching circuitry comprising at least one micro-electromechanical system switch having a beam comprising a first movable actuator and a second movable actuator jointly electrically connected by a common connector and arranged to selectively establish an electrical current path through the first and second movable actuators in response to a single gate control signal applied to respective first and second gates of the switch to actuate the first and second movable actuators of the switch; and 
 a gating circuitry to generate the single gate control signal applied to the first and second gates of the switch, wherein the gating circuitry comprises a driver channel electrically coupled to the common connector of the switch and adapted to electrically float with respect to a varying beam voltage, and electrically referenced between the varying beam voltage and a local electrical ground of the gating circuitry. 
 
     
     
       2. The apparatus of  claim 1 , wherein the common connector comprises an anchor which jointly supports the first and second movable actuators. 
     
     
       3. The apparatus of  claim 1 , wherein the switching circuitry comprises an array of respective micro-electromechanical system switches connected in series circuit to one another to establish the current path through the first and second movable actuators of each respective switch, wherein the gating circuitry comprises a corresponding plurality of further respective gating circuitries each arranged to apply a respective gate control signal to the respective first and second gates of a respective switch to actuate the first and second movable actuators of the respective switch. 
     
     
       4. The apparatus of  claim 3 , wherein the array of respective micro-electromechanical system switches is expandable by way of further micro-electromechanical system connected in parallel circuit, series circuit or both. 
     
     
       5. The apparatus of  claim 4 , wherein the array of respective micro-electromechanical system switches is arranged on-chip, off-chip or both. 
     
     
       6. The apparatus of  claim 3 , wherein each respective gating circuitry comprises a respective driver channel electrically coupled to a respective common connector of the respective switch and adapted to electrically float with respect to a varying beam voltage of the respective switch, and electrically referenced between the varying beam voltage of the respective switch and a local electrical ground of the respective gating circuitry. 
     
     
       7. The apparatus of  claim 3 , wherein the plurality of respective gating circuitries is responsive to a single switching control signal or separate control signals simultaneously or non-simultaneously applied to the plurality of respective gating circuitries. 
     
     
       8. The apparatus of  claim 1 , wherein the gating circuitry comprises a pair of transistors connected to define a half-bridge circuit, wherein a first side of the half-bridge circuit comprises an input stage to receive a voltage level sufficient to actuate the first and second movable actuators when applied to the respective first and second gates of the switch, wherein a second side of the half-bridge circuit is referenced to the potential at the common connector of the switch, and wherein an intermediate node of the half-bridge circuit is electrically coupled to the driver channel and to the first and second gates of the switch to apply the gating signal to actuate the first and second movable actuators of the switch based on a logic level of a switching control signal. 
     
     
       9. The apparatus of  claim 1 , wherein the gating circuitry comprises circuitry selected from the group consisting of a half-bridge circuit, a linear amplifier, a piezoelectric transformer, a charge pump, a converter, and an optically-powered gating circuitry. 
     
     
       10. The apparatus of  claim 8 , wherein the intermediate node of the half bridge circuit is electrically coupled to the first and second gates of the switch by way of a resistive element. 
     
     
       11. The apparatus of  claim 1 , further comprising a power circuitry comprising a first voltage source coupled to a signal conditioning module to generate the voltage level supplied to the input stage of the half bridge circuit, wherein the voltage level is referenced with respect to the potential at the common connector of the switch. 
     
     
       12. The apparatus of  claim 11 , wherein the power circuitry further comprises a second voltage source coupled to a driver of the pair of transistors, the second voltage source arranged to supply a floating voltage to energize a high-side output of the driver of the pair of transistors, the floating voltage being referenced with respect to a potential at the intermediate node of the half-bridge circuit. 
     
     
       13. The apparatus of  claim 12 , wherein the second voltage source can be set to continually supply the floating voltage to energize the high-side output of the driver of the pair of transistors for a relatively long period of time. 
     
     
       14. The apparatus of  claim 1 , further comprising a graded network electrically coupled to the respective micro-electromechanical system switch, the graded network comprising a first resistor-capacitor circuit connected between a first contact connectable to the first movable actuator of the switch and the common connector, the graded network further comprising a second resistor-capacitor circuit connected between a second contact connectable to the second movable actuator of the switch and the common connector, wherein respective time constants of the first and second resistor-capacitor circuits are selected to dynamically balance a transition of the potential at the common connector relative to the respective potentials at the first and second contacts during a switching event. 
     
     
       15. A set of contacts comprising the apparatus of  claim 1 . 
     
     
       16. The switching apparatus of  claim 1 , wherein the electrical current path established by the switching circuitry is operatively coupled to a load, wherein the load comprises a load selected from the group consisting of a direct current (DC) load, an alternating current (AC) load and a radio-frequency (RF) load. 
     
     
       17. The switching apparatus of  claim 1 , wherein the electrical current path established by the switching circuitry is operatively coupled to an alternating current (AC) load, wherein the AC load is selected from the group consisting of a signal having a frequency value relatively lower than a frequency switching speed of the switch, and a signal having a frequency value relatively higher than the frequency switching speed of the switch. 
     
     
       18. The switching apparatus of  claim 1 , further comprising an electrical arcing-protection circuitry coupled across respective contacts of the micro-electromechanical system switch. 
     
     
       19. A switching apparatus comprising:
 a switching circuitry comprising at least one micro-electromechanical system switch having a beam comprising a first movable actuator and a second movable actuator jointly electrically connected by a common connector and arranged to selectively establish an electrical current path through the first and second movable actuators in response to a single gate control signal applied to respective first and second gates of the switch to actuate the first and second movable actuators of the switch; and 
 a gating circuitry to generate the single gate control signal applied to the first and second gates of the switch, wherein the gating circuitry comprises a driver channel electrically coupled to the common connector of the switch and adapted to electrically float with respect to a varying beam voltage, and electrically referenced between the varying beam voltage and a local electrical ground of the gating circuitry, 
 wherein the switching circuitry comprises an array of respective micro-electromechanical system switches connected in series circuit to one another to establish the current path through the first and second movable actuators of each respective switch, wherein the gating circuitry comprises a corresponding plurality of respective gating circuitries each arranged to apply a respective gate control signal to the respective first and second gates of a respective switch to actuate the first and second movable actuators of the respective switch, and 
 wherein each respective gating circuitry comprises a respective driver channel electrically coupled to a respective common connector of the respective switch and adapted to electrically float with respect to a varying beam voltage of the respective switch, and electrically referenced between the varying beam voltage of the respective switch and a local electrical ground of the respective gating circuitry. 
 
     
     
       20. The apparatus of  claim 19 , wherein the array of respective micro-electromechanical system switches is expandable by way of further micro-electromechanical system connected in parallel circuit, series circuit or both. 
     
     
       21. The apparatus of  claim 19 , wherein a respective gating circuitry comprises a pair of transistors connected to define a half-bridge circuit, wherein a first side of the half-bridge circuit comprises an input stage to receive a voltage level sufficient to actuate the first and second movable actuators of the respective switch when applied to the respective first and second gates of the respective switch, wherein a second side of the half-bridge circuit is referenced to the varying beam voltage of the respective switch, and wherein an intermediate node of the half-bridge circuit is electrically coupled to the respective driver channel and to the first and second gates of the respective switch to apply the respective gating signal to actuate the respective first and second movable actuators of the respective switch based on a logic level of a switching control signal. 
     
     
       22. The apparatus of  claim 21 , wherein the intermediate node of the half-bridge circuit is electrically coupled to the first and second gates of the respective switch by way of a resistive element. 
     
     
       23. The apparatus of  claim 22 , further comprising a plurality of respective power circuitries, wherein a respective power circuitry comprises a first voltage source coupled to a signal conditioning module to generate the voltage level supplied to the input stage of the half bridge circuit, wherein the voltage level is referenced to the varying beam voltage of the respective switch. 
     
     
       24. The apparatus of  claim 23 , wherein the respective power circuitry further comprises a second voltage source coupled to a driver of the pair of transistors, the second voltage source arranged to supply a floating voltage to energize a high-side output of the driver of the pair of transistors, the floating voltage being referenced to a potential at the intermediate node of the half-bridge circuit. 
     
     
       25. The apparatus of  claim 24 , wherein the second voltage source can be set to continually supply the floating voltage to energize the high-side output of the driver of the pair of transistors for a relatively long period of time. 
     
     
       26. The apparatus of  claim 20 , further comprising a plurality of graded networks electrically coupled to the plurality of respective micro-electromechanical system switches, wherein a graded network comprises a first resistor-capacitor circuit connected between a first contact connectable to the first movable actuator of the respective switch and the common anchor, the graded network further comprising a second resistor-capacitor circuit connected between a second contact connectable to the second movable actuator of the respective switch and the common anchor, wherein respective time constants of the first and second resistor-capacitor circuits are selected to dynamically balance a transition of the potential at the common anchor relative to the respective potentials at the first and second contacts during a switching event. 
     
     
       27. A set of contacts comprising the apparatus of  claim 20 . 
     
     
       28. A switching apparatus comprising:
 a switching circuitry comprising at least one micro-electromechanical system switch having a first movable actuator and a second movable actuator jointly electrically connected by a common connector and arranged to selectively establish an electrical current path through the first and second movable actuators in response to a single gate control signal applied to respective first and second gates of the switch to actuate the first and second movable actuators of the switch; and 
 a gating circuitry to generate the single gate control signal applied to the first and second gates of the switch, wherein the gating circuitry is electrically referenced to a varying voltage at the common connector of the switch and the common connector is adapted to electrically float with respect to a system ground, and a local electrical ground of the gating circuitry, 
 wherein the switching circuitry comprises a plurality of respective micro-electromechanical system switches connected in series circuit to one another to establish the current path through the first and second movable actuators of each respective switch, wherein the gating circuitry comprises a corresponding plurality of respective gating circuitries each arranged to apply a respective gate control signal to the respective first and second gates of a respective switch to actuate the first and second movable actuators of the respective switch, and 
 wherein each respective gating circuitry is electrically isolated from but electrically referenced to a varying voltage at a respective common connector of the respective switch and the respective common connector is adapted to electrically float with respect to the system ground, and a respective local electrical ground of the respective gating circuitry.